A method for reducing heat and drag on aircraft walls based on aerodynamic metasurfaces

Abstract

The present invention provides a method for reducing heat and drag on the wall of an aircraft based on an aerodynamic metasurface. An aerodynamic metamaterial metasurface is provided on the surface of the aircraft for reducing heat and drag. The metamaterial substrate of the aerodynamic metamaterial metasurface adopts a porous medium material and is densely covered with micro-nano pores that can allow cooling gas inside the aircraft to seep out. Microstructured surface units are periodically arrayed on the surface of the metamaterial substrate, and the microstructured surface units have concave cavities. When an ultra-high-speed incoming flow passes through the aerodynamic metamaterial metasurface, part of the incoming flow gas stays in the concave cavities to form trapped vortices, thereby reducing the shear effect between the incoming flow and the surface of the metamaterial substrate, thereby playing a drag reduction role. The cooling gas seeps out from the surface of the metamaterial substrate from the inner side of the bottom surface of the metamaterial substrate through the micro-nano pores inside the metamaterial substrate, forming a cooling gas film on the surface of the metamaterial substrate, reducing the friction between the mainstream and the surface of the metamaterial substrate, and isolating the heat exchange between the high-enthalpy mainstream and the surface of the metamaterial substrate, thereby playing a heat reduction role.

Description

Technical Field

[0001] The present invention mainly relates to the technical field of aircraft heat reduction and drag reduction, and in particular to a method for reducing heat and drag on the wall of an aircraft based on an aerodynamic metasurface. Background Art

[0002] When an aircraft flies at high speed in the atmosphere, its interaction with air currents generates extremely strong aerodynamic drag and heating, severely limiting its speed and range while also posing significant challenges to its thermal protection. For example, under extreme conditions, the surface friction drag of a waverider-shaped aircraft at high speed can account for up to 80% of the total drag experienced by the aircraft. Consequently, reducing heat and drag has become a bottleneck in the development of ultra-high-speed aircraft.

[0003] Some have also proposed that microgrooved surfaces can effectively reduce wall friction drag. This has gradually broken away from the conventional wisdom that smoother surfaces have lower drag, leading to the development of a variety of surface microstructure drag reduction technologies. Common groove structures include V-shaped, U-shaped, rectangular, and sinusoidal grooves. These utilize the raised ridges of two-dimensional grooves to modify the near-wall boundary layer flow structure. By suppressing boundary layer transition and turbulence, the development of the turbulent boundary layer and the exchange of momentum within the boundary layer are reduced, ultimately leading to a reduction in turbulent friction drag. Current microstructured surface drag reduction solutions typically employ grooves with a size of 0.05-0.1 mm and a drag reduction efficiency of 8%-9%. While this type of drag reduction technology is simple and easy to implement by macroscopically controlling the boundary layer flow structure, its main drawback is that existing grooved surface structures are large in size, resulting in generally low drag reduction efficiency, making them unsuitable for surface drag reduction in hypersonic vehicles. Currently, there are no publicly available design guidelines for the microstructure design of metamaterial surfaces, and existing drag reduction methods fail to address the dual requirements of thermal protection and drag reduction for aircraft. Summary of the Invention

[0004] In response to the technical problems existing in the prior art, the present invention proposes a method for reducing heat and drag on the wall of an aircraft based on an aerodynamic metasurface.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] On the one hand, the present invention provides a method for reducing heat and drag on the wall of an aircraft based on an aerodynamic metasurface, wherein an aerodynamic metamaterial metasurface is provided on the surface of the aircraft where heat and drag reduction is required, the aerodynamic metamaterial metasurface comprising a metamaterial substrate, the metamaterial substrate being made of a porous dielectric material, the metamaterial substrate being densely covered with micro-nanopores capable of allowing internal cooling gas of the aircraft to seep out; the surface of the metamaterial substrate being periodically arrayed with microstructured surface units, the microstructured surface units having concave cavities;

[0007] When ultra-high-speed incoming flow passes through the aerodynamic metamaterial metasurface, part of the incoming gas stays in the concave cavity of the microstructure surface unit to form a trapped vortex, which reduces the shear effect between the incoming flow and the metamaterial substrate surface and plays a drag reduction role.

[0008] The cooling gas seeps out from the inner side of the bottom surface of the metamaterial substrate through the micro-nano pores inside the metamaterial substrate, forming a cooling gas film on the surface of the metamaterial substrate. This reduces the friction between the ultra-high-speed flow on the outside of the metamaterial substrate and the surface of the metamaterial substrate, and at the same time isolates the heat exchange between the high-enthalpy mainstream and the surface of the metamaterial substrate, thereby playing a role in cooling the heat.

[0009] Furthermore, the microstructure surface units on the surface of the metamaterial substrate are arranged in a staggered manner to form a three-dimensional fish-scale surface microstructure.

[0010] Furthermore, the microstructure surface unit includes an inverted trapezoidal cavity and a trapezoidal protrusion, and the inverted trapezoidal cavity and the trapezoidal protrusion are combined to form a microstructure surface unit with a rectangular or parallelogram cross-section.

[0011] Furthermore, the method for determining the structural scale of the microstructure surface unit includes:

[0012] According to the flow parameters of ultra-high-speed incoming flow, the dimensionless thickness scale of the bottom layer of the boundary layer is determined;

[0013] Based on the premise that the depth and opening width of the inverted trapezoidal cavity of the microstructure surface unit should be equivalent to the thickness of the bottom layer of the boundary layer without disturbing the boundary layer, the dimensionless dimensions of the depth and opening width of the inverted trapezoidal cavity of the microstructure surface unit are determined;

[0014] The structural scale of the microstructure surface unit is obtained according to the dimensionless size of the inverted trapezoidal cavity depth and the opening width of the inverted trapezoidal cavity of the microstructure surface unit, including the inverted trapezoidal cavity depth. h , the opening width of the inverted trapezoidal cavity s and the period length of the microstructure surface unit L .

[0015] Furthermore, the micro-nano pores on the metamaterial substrate adopt a micropore scale with a nominal diameter of 5 to 10 microns.

[0016] Furthermore, the porosity of the micro-nano pores on the metamaterial substrate is between 30% and 60%.

[0017] Furthermore, in the method for reducing heat and drag on the wall of an aerodynamic metasurface aircraft, cooling gas seeps out from the inner side of the bottom surface of the metamaterial substrate through the micro-nanopores inside the metamaterial substrate, forming microjets to fill the concave cavities of the microstructured surface units, thereby forming an air-air sliding shear interface with the incoming flow boundary layer above the concave cavities;

[0018] The wall temperature of the aircraft surface that needs to be cooled and drag reduced, measured by the aircraft surface sensor T w Helailiujingwen T ∞ , real-time adjustment of the cooling gas injection rate F The thickness of the cooling film formed after the cooling gas seeps through the surface of the metamaterial substrate can be adjusted, and the thickness of the cooling film can be made equivalent to the cavity depth of the microstructure surface unit, so that the cooling film always remains in the near-wall area of ​​the boundary layer on the outer surface of the aircraft.

[0019] Furthermore, according to the changes in the flight environment of the aircraft and the demand for drag reduction, the seepage rate of the cooling gas and the thickness of the cooling gas film formed after the seepage of the cooling gas are adjusted in real time through the pressure control and flow control devices of the cooling gas supply, thereby adjusting the velocity gradient at the air-air slip shear interface, and then realizing the regulation of flow resistance.

[0020] Compared with the prior art, the present invention can produce the following technical effects:

[0021] This invention proposes a solution for reducing heat and drag on aircraft surfaces based on an aerodynamic metamaterial metasurface. This aerodynamic metasurface (abbreviated as an aerodynamic metasurface) features an internal micro-nanopore percolation structure and a three-dimensional metasurface microstructure. This aerodynamic metasurface utilizes a microscale flow surface created by applying micro-percolation through an artificial microstructure with unique aerodynamic properties. By actively controlling the flow on the microstructured surface, a microscale vortex layer is formed. This significantly reduces the effective frictional contact area between the airflow and the wall, thereby reducing wall friction resistance and aerodynamic heating, achieving large-scale, efficient aerodynamic heat and drag reduction for aircraft.

[0022] Compared with the common groove structures in surface microstructure drag reduction technology, including simple two-dimensional micro-groove drag reduction such as V-shaped, U-shaped, rectangular, circular arc and sinusoidal wavy shapes. The aerodynamic metamaterial metasurface of the present invention has surface micro-nano pores and a three-dimensional fish-scale surface microstructure. On the one hand, it has the effects of "microgroove absorption" and "sound wave scattering", which slows down the transition process of the boundary layer from laminar flow to turbulent flow by suppressing the sound wave disturbance in the boundary layer. On the other hand, the microstructure surface unit includes an inverted trapezoidal cavity and a trapezoidal protrusion, so that the surface convexity and concavity form positive and negative pressure gradients. When the high-speed airflow flows through the aerodynamic metasurface, a second-order vortex is induced in the micro-cavity, and the micro-stationary vortex flow forms a slip flow effect at the bottom of the boundary layer, replacing the strong shear effect between the solid-gas interface on the smooth surface. In this way, the two effects cooperate with each other to effectively reduce the surface friction of the aircraft.

[0023] In terms of heat protection, the aerodynamic metamaterial metasurface uses cooling gas that seeps through the micro- and nano-pores within the metamaterial substrate to push the boundary layer away from the wall, thereby reducing shear friction with the wall and frictional heat generation. At the same time, the seeping gas forms a micro-thin film structure in the bottom layer of the boundary layer, isolating some of the heat from entering the aircraft structure. By changing the flow structure of the bottom layer of the boundary layer through the surface microstructure, surface slip drag reduction is achieved. At the same time, the micro- and nano-pore seepage forms a cooling gas film on the surface, achieving simultaneous heat and drag reduction for hypersonic aircraft. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0025] Figure 1 This is a schematic diagram of the structure of a method for reducing heat and drag on the wall of an aircraft based on an aerodynamic metasurface in one embodiment of the present invention;

[0026] Figure 2 This is a local 3D rendering of the aerodynamic metamaterial metasurface in one embodiment of the present invention;

[0027] Figure 3 Schematic diagram of the structure and size of a microstructure surface unit in one embodiment of the present invention;

[0028] Figure 4 Schematic diagram of the arrangement effect of microstructure surface units in one embodiment of the present invention. DETAILED DESCRIPTION

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0030] Reference Figure 1One embodiment provides a method for reducing heat and drag on an aircraft wall based on an aerodynamic metasurface. An aerodynamic metamaterial metasurface 3 is provided on the aircraft surface where heat and drag reduction is required. The aerodynamic metamaterial metasurface 3 includes a metamaterial substrate 301. The metamaterial substrate 301 is made of a porous dielectric material and is densely covered with micro-nanopores that allow cooling gas 2 inside the aircraft to seep out. Microstructured surface units 302 are periodically arrayed on the surface of the metamaterial substrate. The microstructured surface units 302 have a concave cavity, which in this embodiment is an inverted trapezoidal cavity 303.

[0031] When the ultra-high-speed incoming flow 1 passes through the aerodynamic metamaterial metasurface 3, part of the incoming flow gas stays in the inverted trapezoidal cavity 303 of the microstructure surface unit 302 to form a trapped vortex, which reduces the shear effect between the incoming flow and the metamaterial substrate surface and plays a drag reduction role.

[0032] The cooling gas 2 seeps out from the inner side of the bottom surface of the metamaterial substrate 301 through the micro-nano pores inside the metamaterial substrate 301 and from the surface of the metamaterial substrate 301, forming a cooling gas film on the surface of the metamaterial substrate 301. This reduces the friction between the ultra-high-speed incoming flow 1 on the outside of the metamaterial substrate surface and the surface of the metamaterial substrate 301, and at the same time isolates the heat exchange between the high-enthalpy mainstream and the surface of the metamaterial substrate, thereby reducing heat.

[0033] Furthermore, the structural form of the microstructured surface unit also affects the drag reduction effect. Simulations show that a trapezoidal structure has the best drag reduction effect. The microstructured surface unit 302 includes an inverted trapezoidal cavity 303 and a trapezoidal protrusion 304. The inverted trapezoidal cavity 303 and the trapezoidal protrusion 304 combine to form a microstructured surface unit with a rectangular or parallelogram cross-section. The inverted trapezoidal cavity 303 and the trapezoidal protrusion 304 both have a trapezoidal cross-section, which can be a right-angled trapezoid, an isosceles trapezoid, or other forms.

[0034] The array arrangement of the microstructure surface units 302 will also affect the drag reduction effect. Preferably, the microstructure surface units 302 on the surface of the metamaterial substrate are arranged in a staggered manner to form a three-dimensional fish-scale surface microstructure, forming an overlapping array distribution structure similar to "fish scales", such as Figure 2 and Figure 4 Compared to traditional two-dimensional micro-grooved surfaces, this fish-scale-like three-dimensional biomimetic microstructure surface has better flow adaptability. When the aircraft flies at different angles of attack and yaw, such an aerodynamic metasurface has a drag reduction effect, while the micro-grooved surface only has a drag reduction effect in a specific flow direction.

[0035] The metamaterial substrate surface is periodically arrayed with microstructured surface units 302. If the size of the microstructured surface units 302 is too large, complex compression and expansion waves will appear on the wall, affecting the mainstream of the wall boundary layer, thereby changing the mechanical and thermal distribution on the aircraft surface. The design of the microstructured surface units 302 must be based on the premise of not affecting or slightly affecting the mainstream of the boundary layer. The influence of the characteristic scale of the aerodynamic metamaterial metasurface 3 on the wall friction and heat flow is based on the influence of the characteristic scale of the aerodynamic metamaterial metasurface 3 on the wall friction and heat flow. Figure 1 and Figure 3 The aerodynamic metamaterial metasurface 3 and the microstructure surface unit 302 shown in the figure carry out numerical simulation of boundary layer flow at different characteristic scales. Figure 3 The inverted trapezoidal cavity 303 of the meso-microstructure surface unit 302 is an inverted right-angled trapezoidal cavity, the trapezoidal protrusion 304 is a right-angled trapezoidal protrusion, and the corners of the trapezoidal protrusion 304 are rounded transitionally processed.

[0036] Numerous studies have shown that the drag reduction performance of aerodynamic metamaterial metasurfaces on aircraft is closely related to the shape and structural scale of the microstructured surface unit. Furthermore, one embodiment provides a method for determining the structural scale of the microstructured surface unit 302, including:

[0037] According to the flow parameters of ultra-high-speed incoming flow, the dimensionless thickness scale of the bottom layer of the boundary layer is determined;

[0038] Based on the premise that the depth and opening width of the inverted trapezoidal cavity of the microstructure surface unit should be equivalent to the thickness of the bottom layer of the boundary layer without disturbing the boundary layer, the dimensionless dimensions of the depth and opening width of the inverted trapezoidal cavity of the microstructure surface unit are determined;

[0039] The structural scale of the microstructure surface unit is obtained according to the dimensionless size of the inverted trapezoidal cavity depth and the opening width of the inverted trapezoidal cavity of the microstructure surface unit, including the inverted trapezoidal cavity depth. h , the opening width of the inverted trapezoidal cavity s and the period length of the microstructure surface unit L .

[0040] Specifically, according to the speed of the ultra-high-speed flow u ∞ ,density ρ ∞ , dynamic viscosity v and friction coefficient C f The dimensionless thickness scale y of the bottom layer of the boundary layer is determined by the following parameters: + :

[0041] (1)

[0042] Under the premise of not disturbing the boundary layer, the depth of the inverted trapezoidal cavity of the microstructure surface unit 302 is h and the opening width of the inverted trapezoidal cavity s It should be comparable to the thickness of the bottom layer of the boundary layer, thereby determining the dimensionless dimensions of the inverted trapezoidal cavity depth and the opening width of the inverted trapezoidal cavity of the microstructure surface unit as follows:

[0043] (2)

[0044] (3)

[0045] In the layered structure of turbulence, the viscous bottom layer (0≤y + ≤5) and transition layer (5≤y + ≤30) is collectively referred to as the near-wall region, and its range is approximately 0≤y + ≤30. The formation and development of turbulence mainly occurs in the near-wall region. The generation and dissipation of turbulent kinetic energy in this region plays an important role in the entire turbulent boundary layer. Therefore, the dimensionless dimensions of the inverted trapezoidal cavity depth and the opening width of the inverted trapezoidal cavity of the microstructure surface unit are respectively h + ≤30, s + When ≤30, it has drag reduction characteristics and does not cause strong interference to the boundary layer. h + =15, aspect ratio s / h =1.5, duty cycle N=s / L =0.75 when the drag reduction performance is the best.

[0046] The flow parameters of the ultra-high-speed incoming flow can be determined according to the flight speed and flight altitude of the aircraft, that is, the flow parameters of the ultra-high-speed incoming flow can be determined according to the actual flight speed and flight altitude of the aircraft. u ∞ 、 v 、 C f , and then the physical size of the surface microstructure is obtained according to the dimensionless size optimal parameters.

[0047] Under laminar flow conditions, according to the local Reynolds number Re l The local surface friction coefficient can be estimated according to the empirical formula (4): C f :

[0048] (4)

[0049] In formula (4) l is the distance between the layout position of the aerodynamic metamaterial metasurface on the aircraft and the leading edge of the aircraft.

[0050] According to the friction coefficient level and the incoming flow parameters, the structural scale of the microstructure surface unit can be estimated, including the depth of the inverted trapezoidal cavity. h , the opening width of the inverted trapezoidal cavity s and the period length of the microstructure surface unit L , the specific expression is:

[0051] (5)

[0052] in u ∞ Indicates the speed of the ultra-high-speed incoming flow, l is the distance between the layout position of the aerodynamic metamaterial metasurface and the leading edge of the aircraft, v Indicates the dynamic viscosity of ultra-high-speed incoming flow, N Indicates the duty cycle.

[0053] Key parameters for micro-nanopores to suppress boundary layer disturbances include surface porosity, pore depth, and nominal pore radius. The optimal porosity is related to flow direction and position; the micro-nanopores on the metamaterial substrate described herein have a porosity between 30% and 60%. The optimal pore radius is not significantly related to flow direction. To minimize the normal perturbation velocity of microporous flow and prevent it from penetrating the underlying boundary layer, the micro-nanopores on the metamaterial substrate described herein have a nominal diameter of 5-10 microns.

[0054] The cooling gas 2 seeps out from the inner side of the bottom surface of the metamaterial substrate through the micro-nano pores inside the metamaterial substrate and then forms a micro-jet to fill the cavity of the microstructure surface unit, thereby forming an air-air sliding shear interface with the incoming flow boundary layer above the cavity, as shown in FIG. Figure 1 shown.

[0055] The cooling gas 2 seeps out from the inner side of the bottom surface of the metamaterial substrate 301 through the micro-nano pores inside the metamaterial substrate 301 and forms a cooling gas film on the surface of the metamaterial substrate 301. The cooling gas film is fully sheared and obtains a velocity tangential to the wall. u e ( u e is the velocity at the outer edge of the incoming boundary layer), the thickness of the cooling film formed by the cooling gas is δ , according to the continuity equation:

[0056] (6)

[0057] Where, ρ,u Indicates the density and velocity of the fluid, the following table f Represents the cooling gas parameters, the following table e represents the flow parameters at the outer edge of the incoming boundary layer,s is the length of the blowing interval, that is, the flow length of the porous wall, is the mass flow rate of the cooling gas. According to the injection rate of the cooling gas F The definition of ), which can be further expressed as:

[0058] (7)

[0059] Assuming that the cooling gas seeping out of the metamaterial substrate surface reaches thermal equilibrium with the metamaterial substrate (similar to a porous medium skeleton), the ideal gas state equation can be obtained:

[0060] (8)

[0061] Where, M represents the molar mass of the gas, p e is the incoming boundary layer pressure, T e is the temperature at the outer edge of the boundary layer, T w is the wall temperature, R is the molar gas constant. Thus,

[0062] (9)

[0063] When the cooling gas is room temperature air, the above formula is further simplified to:

[0064] (10)

[0065] The wall temperature of the aircraft surface that needs to be cooled and drag reduced, measured by the aircraft surface sensor T w Helailiujingwen T ∞ , real-time adjustment of the cooling gas injection rate F The thickness of the cooling film formed after the cooling gas seeps through the surface of the metamaterial substrate can be adjusted, and the thickness of the cooling film can be made equivalent to the cavity depth of the microstructure surface unit, so that the cooling film always remains in the near-wall area of ​​the boundary layer on the outer surface of the aircraft.

[0066] According to the changes in the flight environment and drag reduction requirements of the aircraft, the pressure control and flow control devices of the cooling gas supply are used to adjust the cooling gas seepage rate and the thickness of the cooling gas film formed after the cooling gas seeps in real time, thereby adjusting the velocity gradient at the air-air slip shear interface and achieving the regulation of flow resistance.

[0067] The present invention provides a method for reducing heat and drag on the wall of an aircraft based on an aerodynamic metasurface. By utilizing an aerodynamic metamaterial metasurface, the surface friction of an ultra-high-speed aircraft can be reduced over a large area with high efficiency, and a stable and continuous seepage air film sliding boundary layer can be formed without consuming additional energy.

[0068] Matters not covered by the present invention are known technologies.

[0069] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0070] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and such modifications and improvements are intended to fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims.

[0071] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for reducing heat and drag on the wall of an aerodynamic metasurface aircraft, characterized in that: An aerodynamic metamaterial metasurface is provided on the surface of an aircraft requiring heat and drag reduction. The aerodynamic metamaterial metasurface includes a metamaterial substrate, the metamaterial substrate is made of a porous medium material, and the metamaterial substrate is densely covered with micro-nanopores capable of allowing internal cooling gas of the aircraft to seep outward; microstructured surface units are periodically arrayed on the surface of the metamaterial substrate, and the microstructured surface units have cavities; the microstructured surface units include inverted trapezoidal cavities and trapezoidal protrusions, and the inverted trapezoidal cavities and trapezoidal protrusions are combined to form a microstructured surface unit with a rectangular or parallelogram cross-section. A method for determining the structural scale of the microstructured surface unit includes: According to the flow parameters of ultra-high-speed incoming flow, the dimensionless thickness scale of the bottom layer of the boundary layer is determined; Based on the premise that the depth and opening width of the inverted trapezoidal cavity of the microstructure surface unit should be equivalent to the thickness of the bottom layer of the boundary layer without disturbing the boundary layer, the dimensionless dimensions of the depth and opening width of the inverted trapezoidal cavity of the microstructure surface unit are determined; The structural scale of the microstructure surface unit is obtained according to the dimensionless size of the inverted trapezoidal cavity depth and the opening width of the inverted trapezoidal cavity of the microstructure surface unit, including the inverted trapezoidal cavity depth. , the opening width of the inverted trapezoidal cavity and the period length of the microstructure surface unit ， for: in Indicates the speed of the ultra-high-speed incoming flow, is the distance between the layout position of the aerodynamic metamaterial metasurface and the leading edge of the aircraft, Indicates the dynamic viscosity of ultra-high-speed incoming flow, Indicates duty cycle; When ultra-high-speed incoming flow passes through the aerodynamic metamaterial metasurface, part of the incoming gas stays in the concave cavity of the microstructure surface unit to form a trapped vortex, which reduces the shear effect between the incoming flow and the metamaterial substrate surface and plays a drag reduction role. The cooling gas seeps out from the inner side of the bottom surface of the metamaterial substrate through the micro-nano pores inside the metamaterial substrate, forming a cooling gas film on the surface of the metamaterial substrate. This reduces the friction between the ultra-high-speed flow on the outside of the metamaterial substrate and the surface of the metamaterial substrate, and at the same time isolates the heat exchange between the high-enthalpy mainstream and the surface of the metamaterial substrate, thereby playing a role in cooling the heat.

2. The method for reducing heat and drag on the wall of an aerodynamic metasurface aircraft according to claim 1, characterized in that: The microstructure surface units on the surface of the metamaterial substrate are arranged in a staggered manner to form a three-dimensional fish-scale surface microstructure.

3. The method for reducing heat and drag on the wall of an aerodynamic metasurface aircraft according to claim 1, characterized in that: Duty cycle .

4. The method for reducing heat and drag on the wall of an aircraft based on an aerodynamic metasurface according to claim 1, 2 or 3, characterized in that: The micro-nano pores on the metamaterial substrate adopt a micropore scale with a nominal diameter of 5 to 10 microns.

5. The method for reducing heat and drag on the wall of an aircraft based on an aerodynamic metasurface according to claim 4, characterized in that: The micro-nano pore opening rate on the metamaterial substrate is between 30% and 60%.

6. The method for reducing heat and drag on the wall of an aircraft based on an aerodynamic metasurface according to claim 1, 2, 3 or 5, characterized in that: The cooling gas seeps out from the inner side of the bottom surface of the metamaterial substrate through the micro-nano pores inside the metamaterial substrate and then forms a micro-jets to fill the concave cavity of the microstructure surface unit, thereby forming an air-air sliding shear interface with the incoming flow boundary layer above the concave cavity; The wall temperature of the aircraft surface that needs to be cooled and drag reduced, measured by the aircraft surface sensor T w Helailiujingwen T ∞ , real-time adjustment of the cooling gas injection rate F The thickness of the cooling film formed after the cooling gas seeps through the surface of the metamaterial substrate can be adjusted, and the thickness of the cooling film can be made equivalent to the cavity depth of the microstructure surface unit, so that the cooling film always remains in the near-wall area of ​​the boundary layer on the outer surface of the aircraft.

7. The method for reducing heat and drag on the wall of an aircraft based on an aerodynamic metasurface according to claim 6, characterized in that: According to the changes in the flight environment and drag reduction requirements of the aircraft, the pressure control and flow control devices of the cooling gas supply are used to adjust the cooling gas seepage rate and the thickness of the cooling gas film formed after the cooling gas seeps in real time, thereby adjusting the velocity gradient at the air-air slip shear interface and achieving the regulation of flow resistance.

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